A098478 - OEIS

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A098478

Expansion of 1/sqrt(1-2x-11x^2+12x^3).

1, 1, 7, 13, 73, 187, 895, 2737, 11923, 40333, 166753, 598111, 2404309, 8926651, 35365651, 134054005, 527360581, 2024611351, 7940840719, 30733601689, 120439122811, 468630460885, 1836912780541, 7173754477099, 28140632060899 (list; graph; refs; listen; history; internal format)

	OFFSET	`0,3`
	COMMENTS	`1/sqrt(1-2x-(4r-1)x^2+4r^3) expands to give sum{k=0..floor(n/2), binomial(2k,k)binomial(n-k,n-2k)r^k}`
	FORMULA	`a(n)=sum{k=0..floor(n/2), binomial(2k, k)binomial(n-k, n-2k)3^k}`
	CROSSREFS	`Cf. A026569, A098477.` `Sequence in context: A159198 A106976 A138077 * A174878 A177198 A177163` `Adjacent sequences: A098475 A098476 A098477 * A098479 A098480 A098481`
	KEYWORD	`nonn`
	AUTHOR	`Paul Barry (pbarry(AT)wit.ie), Sep 10 2004`

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Last modified February 17 16:49 EST 2012. Contains 206058 sequences.